Abstract

In specialised veterinary hospitals, Magnetic Resonance Imaging (MRI) scanners are used daily in diagnostics of dogs. MRI scanners omit high levels of acoustic noise, which is known to be damaging to the hearing of human patients without effective ear protection. However, the effects of the MRI noise levels on the cochlear function and hearing of dogs is often overlooked and in many clinics, dogs are not provided with ear protection for the duration of their scan. The aim of this study was to assess the effects of MRI acoustic noise on the cochlear function of dogs, by Distortion Product Otoacoustic Emissions (DPOAE) testing dogs immediately before and after they underwent an MRI scan. A group of control dogs undergoing a quiet procedure (but treated with the same range of anaesthetic drugs) were also tested. Post-MRI, the mean DPOAE of the dogs was reduced at all frequencies tested, significantly so at five (out of fourteen) frequencies, reflecting a reduction in cochlear function. Furthermore, at all frequencies tested, more than half of the ears exposed to MRI noise demonstrated a decrease in DPOAE. Without repeat DPOAE testing of the dogs some weeks after their MRI, it is unknown whether this effect is temporary and reversible, or permanent. Nevertheless, the results support a recommendation that all dogs undergoing an MRI scan are provided with ear protection as a precautionary measure.